The subject matter disclosed herein relates to combustor systems, and more particularly to an air management arrangement for a late lean injection combustor system, as well as a method of routing an airflow within such a late lean injection combustor system.
In combustion applications, such as a gas turbine system, for example, a combustor section includes a combustor chamber defined by a combustor liner that is often surrounded by a sleeve, such as a flow sleeve. An airflow typically passes through a passage disposed between the combustor liner and the sleeve for cooling of the combustor liner, as well as routing of the airflow to air-fuel injectors located at a forward end of the combustor liner. The airflow is derived from an air supply that must typically also provide air to other regions for a variety of purposes. Such a region may include late lean injectors that inject air into the combustor chamber in an effort to reduce undesirable emissions into an ambient atmosphere. As late lean injection combustor systems become more prevalent and more of the air supply is employed to provide air to the late lean injectors, efforts to cool the combustor liner are hindered due to the availability of less air from the air supply to be used for cooling purposes within the passage between the sleeve and the combustor liner.
Based on the direct supply of airflow to the air-fuel injectors, a combustion system is subject to back pressure when combustion fluctuates and suddenly increases the combustion pressure. The higher pressure inside the combustor chamber will instantaneously “push” a flammable fuel/air mixture into an air supply chamber, such as a compressor discharge casing (CDC). Such flammable mixture may cause damage to the CDC and result in shut down.